Photographic apparatus and process employing porous filter

ABSTRACT

Photographic apparatus employing a gas-excluding filter interposed between a source of processing liquid and a processing chamber for providing a flow of gas-free processing liquid to exposed photographic material disposed within the processing chamber. Preferably, the source of liquid is provided within a disposable, variable-volume container or container-filter combination adapted for coupling to a processing chamber of a camera which includes a force supplying member for varying the volume of the reservoir-container so as to selectively vary the pressure differential across the filter and thereby direct gasfree processing liquid to or from the processing chamber. A transport element is included in the camera for positioning the exposed photographic material in the processing chamber pripr to dispensing of the liquid thereto and for removal of the liquidtreated photographic material subsequent to extraction of excess liquid from the chamber.

United States Patent Dietz et al. 1

[451 May 2,1972

54] PHOTOGRAPHIC APPARATUS AND PROCESS EMPLOYING POROUS FILTER [72] Inventors: Milton S. Dietz, Lexington; Walter G.

Lehamann, Somerville, both of Mass.

[73] Assignee: Polaroid Corporation, Cambridge, Mass.

[22] Filed: Jan. 5, 1971 21 App1.No.: 104,062

[52] U.S. Cl. ..95/13, 95/89 R, 118/266, 222/103, 222/189 [51] Int. Cl. ..G03b 17/50 [58] Field of Search ..95/13, 89 R; 118/264, 265, 118/266, 267; 222/189, 214, 213, 103; 401/206 Robin et al ..95/89 R x Primary Examiner-Samuel S. Matthews Assistant Examiner-Richard L. Moses Attorney-David R. Thornton [57] ABSTRACT Photographic apparatus employing a gas-excluding filter interposed between a source of processing liquid and a processing chamber for providing a flow of gas-free processing liquid to exposed photographic material disposed within the processing chamber. Preferably, the source of liquid is provided within a disposable, variable-volume container or container-filter combination adapted for coupling to a processing chamber of a camera which includes a force supplying member for varying the volume of the reservoir-container so as to selectively vary the pressure differential across the filter and thereby direct gas-free processing liquid to or from the processing chamber. A transport element is included in the camera for positioning the exposed photographic material in the processing chamber pripr to dispensing of the liquid thereto and for removal of the liquid-treated photographic material subsequent to extraction of excess liquid from the chamber.

29 Claims, 7 Drawing Figures PHOTOGRAPI-IIC APPARATUS AND PROCESS EMPLOYING POROUS FILTER BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to photographic apparatus and, more articularly, to photographic apparatus, and a process, for treating photographic material with processing liquid.

2. Description of the Prior Art Photographic apparatus and photographic processes of the type with which the present invention is concerned generally involve exposure of a photosensitive image-recording sheet and subsequent distribution of a liquid reagent over the exposed sheet for developing purposes. This distribution is often accomplished by transporting the photosensitive sheet material into contact with a source of liquid, for example, by immersing the photographic material in a container filled with developer solution. Generally, this method subjects all of the liquid source to exposure to the atmosphere, at least during insertion and removal of the photosensitive sheet.

The processing liquid may also be dispensed to the photographic material, for example, by filling and draining a film tank so as to inundate an enclosed sheet of material, However,

air or other gas is inadvertently included in the liquid, either during initial filling of the reservoir containing the source of liquid or during draining of the film tank, and prevents complete, uniform wetting of the sheet material. Hence, this requires the use of a sufficiently wide tank to allow the gas to rapidly escape to the liquid surface and is, of course, impractical since it not only requires a large amount of space and of processing liquid but also necessitates an excessively long time for filling and draining of the chamber. 7

Additionally, application of the processing liquid in portable apparatus such as a camera, with which the present invention is particularly concerned, further compounds the difficulties of storing and applying the liquid to successive photographic sheets since this often requires the application of accurately predetermined quantities of the liquid, uniformly and at relatively high rates, and the necessity for so doing intermittently with constant reproducible results in apparatus that presents the problem of precluding spillage.

Accordingly, an important object of this invention is to provide improved photographic apparatus for facilitating processing of photographic material.

An additional object of this invention is to provide apparatus for rapidly applying a selected amount of processing liquid to expose photographic material without inclusion of entrained gaseous fluids in the applied liquid.

Another object of this invention is to provide an improved compact camera of the self-developing type for exposing and processing of photographic sheet material.

A still further object of thisinvention is to provide an improved method for treating photographic material with processing liquid.

Also an object of this invention is to provide a disposable dispenser of processing liquid which is adapted for mounting on photographic apparatus for applying selected amounts of processing liquid over successive sheets of photographic material.

SUMMARY OF THE INVENTION This invention concerns photographic apparatus for rapidly applying processing liquid to a sheet of exposed photographic material for processing thereof. The apparatus provides means for selectively effecting a flow of processing liquid from a source thereof to the photographic material, following its exposure, and for precluding passage of gaseous fluid from such source to such-material so as to dispense such liquid over said material without inclusion of entrained gas in the dispensed portion. 1

In its illustrated embodiment, the invention briefly comprises a camera of the self-developing type having a source of tainer which is releasably mounted on the camera in communication with a processing chamber thereof through a porous filter medium adapted to permit passage of the processing liquid within a given range of applied pressure differential while precluding passage of gaseous fluid, and includes means for varying the volume of said container for selectively establishing a predetermined pressure differential on 'said filter medium for selectively effecting a flow of gas-free liquid between said source and said processing station so as to apply a liquid portion to such film material when it is positioned within said processing chamber and to subsequently remove the unimbibed excess of such liquid portions from said processing chamber.

Preferably, the processing chamber is a thin elongated container adapted to have the photographic material disposed therein following its exposure, and the liquid source is provided in a disposable dispenser which includes a container for receiving the source of liquid and a porous filter adapted for coupling to the processing chamber. The container of liquid is preferably a deformable bladder of elastic material, and the camera includes a force applying means adapted to selectively deform the container and thereby vary the pressure differential across the porous filter so as to effect reversible flow of the liquid between the container and the processing chamber without inclusion of gaseous fluid within the transported liquid.

Briefly, the process for treating exposed photographic film material with processing liquid comprises the steps of conducting liquid and precluding conduction of gaseous fluids from a source of processing liquid to said photographic material, and returning excess unimbibed liquid to said source while precluding passage of gaseous fluid from said photographic material to said source.

BRIEF DESCRIPTION OF THE DRAWINGS The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and, its method of operation, together with additional objects and advantages thereof will best be understood from the following description of the preferred embodiments when read in connection with'the accompanying drawings wherein like numbers have been employed in the different figures to denote the same parts and wherein:

FIG. 1 is a diagrammatic view in perspective of a camera embodying the invention and performing the process thereof;

FIG. 2 is a diagrammatic view in perspective of the precessing station employed in the camera of FIG. 1;

FIGS. 3, 4, 5 and 6 are sectional views of the camera of FIG. 1 illustrating operation of the processing system; and

'FIG. 7 is a diagrammatic view of an alternative embodiment of the processing chamber.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENT The preferred embodiment of this invention is illustrated as a camera apparatus facilitating the application of compatible processingliquid to a photosensitive image-recording sheet following its exposure. The apparatus is adapted for photoexposure of an area of the image-recording sheet to form an image therein, distribution of a processing liquid over at least the exposed area of the sheet, and superposition of this sheet with animage-receiving sheet for formation of a visible image in the latter by a diffusion-transfer process. The apparatus and process of the invention, while applicable to photography in general, are specially adapted to produce photographic transfer prints such as those described in U. S. Pat. No. 2,983,606 issued May 9, 1961 to Howard G. Rogers and utilizing integral multilayer image-recording sheets incorporating dye developers such as are disclosed in U. S. Pat. No. 3,345,163 issued Oct. 3, 1967 to Edwin H. Land et al., andto photographic film processing as described in U. S. Pat. No. 3,485,628 issued Dec. 23, 1969 to Edwin H. Land. As in dicated in the latter patent, the multicolor image-recording sheet is first photoexposed to form a latent image, then permeated with an aqueous alkaline processing liquid, and super posed with an image-receiving sheet so as to produce a visible image therein.

As shown in FIGS. 1, 3 and 4, the camera includes a housing having a conventional lens and shutter assembly 12 (see FIGS. 3 and 4) adapted to expose a suitable photosensitive sheet 18 presented at an exposure aperture 14. Means are provided in the upper rear portion of the camera housing for mounting a film pack or magazine 16 containing a plurality of the image-recording sheets 18 for exposure of each foremost sheet successively to light transmitted by lens and shutter assembly 12 through aperture 14. These means include an opening 17 in the rear of the camera which is adapted to releasably receive magazine 16, and the latter includes conventional arrangement, later described in detail, for positioning the foremost image-recording sheet substantially in a plane disposed perpendicular to the axis of lens and shutter assembly 12.

Magazine 16 comprises an open-face box or container 20 in which is mounted a pressure plate 22 biased towards the front of the container by a spring 24. The front face of the container 20 includes a rectangular opening 25 having a flange 26 along opposite edges of the opening which in cooperation with spring 24 provide means for positioning each sheet 18 at the exposure aperture 14 and for guiding each sheet in the focal plane during its withdrawal from the magazine 16.

Beneath the lens assembly at the front of the camera is mounted a second magazine 30 which contains a plurality of image-receiving sheets 32 in stacked relation within a box-like container 34, with the sheets disposed in planes generally perpendicular to the planes of image-recording sheets 18. Magazine 30 includes a spring member 35 for urging the sheets against the lower face 37 of the container 34 into lateral alignment with an exit aperture 38, and additionally includes a slide member 36 mounted along one side of the container for engagement of the lowermost sheet of the stack so as to urge it rearwardly in accordance with operation of the camera, as later explained in detail.

Mounted at the base of the housing 10 is a processing station 40, which as shown in detail in FIG. 2, includes a tank or enclosure 41 having a thin or narrow processing chamber 42 in communication with a deformable bladder-like container 44, of a source of liquid 48, through a porous filter membrane 46 which permits liquid flow, but precludes gas passage between container 44 and chamber 42 so as to insure complete and uniform wetting of the film sheet 18 when it is positioned within the chamber. Consequently, the novel filter arrangement permits very rapid filling of the chamber 42 with gas-free liquid and excludes gas intake into the container during reverse flow to the source.

As practiced in the invention, filter 46 is a so-called membrane filter of microporous material having a sponge-like structure of small enough pore size so as to provide a relatively high bubble pressure in the processing liquids. Suitable membrane materials are glass, ceramic, carbon, or plastic material such as nylon or polyvinyl chloride, or'other materials which are chemically inactive with the processing liquid and have a sufficiently small pore size such that once contracted with the liquid, it will pass the same and exclude passage of gas upon application of a low range of pressure differential. Stated otherwise, the filter is of a porous substance of sufficiently small pore size, (for example, 0.5 to 10 microns) which in cooperation with the surface tension of the liquid, is liquid permeable but substantially gas impermeable within a given range of pressure differential. Consequently, the processing unit 40 is adapted to rapidly and reversibly transport gas-free liquid between the source 48 and the film chamber 42.

In this embodiment, processing chamber 42 is designed to accept the image-recording sheet after its exposure and retain it therein while the sheet is inundated with liquid dispensed from source 48. Chamber 42 is generally parallelepiped in shape, relatively narrow from front to back forming, for example, a 4; inch wide cavity, and is at least equal in depth and width to the dimensions of the image-recording sheet 18 such that the latter may be positioned in the chamber without portions projecting therefrom. A sealing member 50, disposed near the top of the chamber 42, is adapted to close and seal the chamber following deposit of the exposed image-recording sheet therein. Included at the top of the chamber 42 is a baffie member 52 for controlling the direction of motion of the sheet during its extraction, and a lever arm 54 is pivotally mounted at the bottom of the chamber for ejecting sheets following their imbibition of processing liquid 48. Conventional sealing means (not shown) are employed to seal the opening where lever 54 extends from the chamber 42. Also included within chamber 42 is a gas venting means 56 which is mounted within the side wall of the chamber interiorly of sealing member 50 and adapted to permit escape of gas from the chamber as it is filled and the intake of gas into the chamber as it is emptied of liquid. In this embodiment, container 44 with its filter 46 is a disposable unit adapted to be releasably mounted within housing 10 in communication with chamber 42. For example, the unit is configured to fit within housing 10 with the filter body 46, which is located within the front edge of an elongated base 58 of the reservoir, in releasable engagement with an opening 59 of the chamber 42. Advantageously, the container-filter combination may be temporarily sealed by the manufacturer after filling with liquid, for example, by applying pressure sensitive tape or the like across the filter 46 which is exterior to the container 44. As illustrated, membrane filter 46 provides a common or party wall between the container 44 and the chamber 42. In a specific example, which is given for purposes of illustration and not intended to be limiting, a 3x4 inch sheet of photosensitive material of the type disclosed in the aforementioned U. S. Pat. No. 2,983,606 was processed with an aqueous alkaline solution having a low viscosity, substantially that of water, and containing:

Percent Potassium hydroxide 10.0 N-benzyl-a-picolinium bromide 2.0 Benzotriazole 3 .5 Zinc nitrate 05 After exposure, the photosensitive sheet was positioned within the described chamber which was in communication with a bladder container, formed of flexible 0.025 inch thick polyethylene, through a filter membrane 140 micron thick and having approximately a 2 inch square surface. The filter membrane was constructed of a nylon reinforced, acrylonitrile polyvinylchloride copolymer having a mean pore size of 1.2 micron and a porosity of approximately 70 percent. The processing liquid was dispensed into the chamber by compressing the bladder container so as to apply a pressure differential across the membrane of slightly under 5 psi and to fill the chamber with gas-free liquid in under 1 second. Then, after 8 seconds, the chamber was drained by releasing the compressive force from the bladder, and the photosensitive sheet was then removed from the chamber and immediately pressed into face-to-face contact with an image-receiving sheet to produce a visible image in the latter.

Mounted within the camera housing 10 is a transport mechanism 60, including a plurality of feed rolls 62 and a cam mechanism 64, for providing transport of the film sheets and operation of processing unit 40 as illustrated in FIGS. 3-6. Feed rolls 62 and cam mechanism 64 are both operated from a single power means 66, for example, a battery operated electric motor or the like, by conventional V-belts as shown at 68. Other power means, including manual operation by a hand crank, etc., would be suitable. Cam mechanism 64 is a multifaced cam unit coupled by cam followers or the like to lever members 72, 74, 76, 78 and 80 which cooperate with feed rolls 62 to process an exposed image-recording sheet 18, superpose it with an image-receiving sheet 32 and deliver them in superposition from housing 10. In this embodiment, three rolls 80, 82 and 84 are driven from motor 66 in the directions as shown by the arrows in FIG. 3, while one roll 86 is an idler. Each roll includes a surface of resiliently deformable material such as an elastomer having a high coefficient of friction to facilitate gripping and advancement of the sheets. The feed roll 80 is positioned alongside the roll 86 and located beneath film magazine 16 in position to advance image-recording sheets 18 downwardly to processing station 40, and the roll 82 is located beneath the roll 86 in position to advance an imagereceiving sheet 32 rearwardly. Finally, the roll 84 is placed slightly rearwardly and below the roll 80 so as to superpose and eject both sheets in superposition following imbibition of sheet 18. y

In operation of the camera, once the foremost imagerecording sheet 18 has been exposed, the transport mechanism 60 is activated by any conventional means, for example, by switching on motor 66 or the like which drives feed rolls 62 and cam mechanism 64. At this point in the operation, the component parts are positioned as shown in FIG. 3. As the cam unit 64 begins to rotate in the counterclockwise direction shown, the foremost image-recording sheet 18 is driven downwardly by lever'72 so as to enter the bite of rollers 80 and 86 for delivery to chamber 42 as illustrated in FIG. 4. At this stage, baffle member 52 is held in vertical position and sealing member 50 is held open by lever members 74 and 76, respectively, so as to allow chamber 42 to receive the image-recording sheet 18. As cam 64 continues to rotate, lever 76 is drawn forwardly towards the front of housing to move sealing member 50 to a closed position, and subsequently, lever 80 is moved rearwardly to deform reservoir-container 44 so as to apply a suitable pressure differential to membrane 46 and to inject liquid from source 48 to the processing chamber 42. Deformation of the container 44 is achieved by pressure plate 90 which is coupled to force applying lever 80 through a spring 92 and a pivotally mounted lever arm 94. As container 44 is deformed, or that is, compressed in accordance with the force applied by plate 90, a positive pressure is applied on source 48 and a positive pressure differential established on filter 46 which is connected to chamber 42 and at atmospheric pressure. Consequently, liquid is forced from the source 48 in a gas-free condition to the chamber 42 where it inundates the enclosed film sheet. Once the liquid reaches the level of vent 56, its ball valve 57 automatically closes to seal the chamber 42. This equalizes the pressure differential across the filter 46 and cuts off further liquid flow. The unit is constructed such that'the pressure differential is controlled within a range of zero to 5 psi during this phase of the operation so as to exclude gas from passing through the filter 46. After a suitable imbibition time, thatis, for example, approximately 8 seconds, the continued rotation of cam 64 operates to reverse the liquid flow. That is, further rotation releases lever 80 whereby the elastic reservoir 44 tends to return to its original volume which decreases the pressure on source 48 and applies a negative pressure differential to the filter 46 so as to withdraw the liquid from chamber 42. Reduction of the pressure in container 44 inherently reduces the pressure in chamber 42 and opens vent 56. At this time, air or other gas is precluded from entering container 44 by the filter 46. Further rotation of cam 64 then operates levers 74, 76 and 78 in sequence to incline baffle 52, open sealing member 50 and activate lever 54 which ejects the imbibed image-recording sheet upward from the chamber 42 as shown in FIG. 6. As the image-recording sheet 18 leaves the chamber, it is diverted by baffle member 52 to the bite of the exit rolls 80 and 84 which withdraw it from the chamber. During ejection of the image-recording sheet 18, the lowermost image-receiving sheet 32 is simultaneously ejected from its magazine 30, advanced through rolls 82 and 86 to meet the imbibed image-recording sheet, and subsequently advanced in superposition therewith through the exit rolls'80 and 84 and from the apparatus. This simultaneous ejection of 34.' At this stage, the camera is now ready for processing of the next successive sheet.

In this embodiment, the maximum pressure differential applied across filter 46 is a function of the cam displacement of lever 80, the compression factor of spring 92 and the elasticity of reservoir 44. These are easily adjusted to apply a pressure differential to filter 46 which remains within the range of pressure differential to exclude gas but of sufficient magnitude to rapidly dispense the liquid. Although a small amount of liquid permeates, or is lost to, each successive sheet, and the volume of the liquid source thereby constantly decreases, the pressure differential achieved during eachsuccessive deformation of the reservoir-chamber 44 is maintained substantially constant since spring 92 operates to apply a constant compression force to the chamber. That is, although with decreasing volume of the liquid source 48, pressure plate 90 must additionally deform reservoir 44 to repetitively achieve pressure differentials of equal value, this is automatically achieved by spring 92 which elastically couples the-pressure plate to lever arm 80 and converts its constant displacement to a constant force on plate 90.

For proper filling and draining of the chamber, it is necessary that the illustrated structure be operated with processing station 40 in an upright position whereby filter 46 will be near the bottom of source'48 and venting means 56 at the top of the chamber 42. However, at any time other than the actual filling or draining of the chamber, the apparatus may be disposed in any particular attitude.

In an alternative embodiment, illustrated in FIG. 7, the processing station is adapted to enclose only the photosensitive area of an image-recording sheet 18. In this embodiment, the film enclosure or liquid-receiving chamber 42 is formed by engagement of the image-recording sheet 18 between a first member and a second member 102.

Member 100 includes a cavity 104 and a perimetric sealing means or gasket 106 of elastomeric material located at the open end of the cavity so as to form sealing engagement with margins of the image-recording sheet 18 and thereby enclose its photoexposed area. Coupled to cavity 104 is the container 44 and the membrane filter 46. The second member 102 is of substantially rigid material, and is adapted to press the imagereceiving sheet into sealing contact with gasket 106 and also support the photosensitized area of the sheet when the cavity is filled with liquid. A plurality of levers members 110 are affixed to member 102 and adapted to impart a translational motion to the latter member in a direction toward or away from cavity-member 100 so as to permit insertion and removal of sheet 18 therebetween.

Advantageously, this processing station may be adapted for use in the apparatus of the preferred embodiment, in which case the transport means and means for applying a pressure difierential to the filter, etc., may remain unchanged. However, the fact that margin portions of sheet 18 extend at one or more edges of the processing enclosure simplify the positioning of the film sheet within the processing station. For example, the lever means utilized in the preferred embodiment to eject the image-recording sheet from the processing station need no longer enter the actual enclosure but may be disposed external thereto for engagement of a sheet margin. Moreover, a leading edge of the image-receiving sheet may be utilized to engage the extended edge of the image-recording sheet so as to withdraw the same in accordance with the apparatus described in the aforementioned U. 8. Pat. No. 3,405,618 issued on Oct. 15, 1968 to Edwin H. Land et al.

As in the preferred embodiment, means for venting the enclosure are provided at the top of the cavity 104. Herein, an alternative vent, which is applicable to the chamber of either embodiment, is illustrated. In this case, the venting means is a filter membrane 114 which is disposed in a blocking arrangement across a conduit 1 16 which extends from cavity 104. The membrane 114 is constructed of porous filter material which will allow passage of gaseous fluids until it is contacted by the liquid whose passage is precluded. That is, membrane 114 is of small pore material which is substantially impervious to the liquid. For example, a 0.005 inch thick film of polytetrafluoroethylene having a mean pore size of approximately microns and a percent porosity of about 60 percent suitably exclude passage of the liquid at pressures indicated for chamber operation.

The processing apparatus and method of the invention may be realized in many different forms. Any transport mechanism,including manual operation, adapted for insertion and removal of the film from an enclosure, such as, for example, that shown in the aforementioned U. S. Pat. No. 3,405,618 could be employed with the filter arrangement of the invention in combination with suitable means for applying a controlled pressure differential between the source of processing liquid and the film enclosure.

Many other variations and different embodiments are also possible within the scope of these teachings. For instance, in certain applications it may be desirable to utilize a conventional pump or other means for varying the pressure of either side of the filter to provide a suitable pressure differential. Moreover, the exposure station and the film chamber may be suitably combined to make a more compact unit. Hence, those familiar with the photographic arts will readily appreciate the novel and highly unique advantages of this invention which provides apparatus facilitating rapid processing of photographic material with substantially non-viscous liquid provided within a compact disposable source adapted to selectively dispense predetermined amounts of gas-free liquid for application to the photographic material.

Since these and other variations of the invention and its modes of utilization may be made within the scope of the present teachings, the preferred embodiments described herein is therefore illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all variations which come within the meaning of the claims are intended to be embraced therein.

What is claimed is:

1. A camera for exposing photographic material and for applying processing liquid from a source thereof to such material, said camera comprising:

means for receiving such material in an exposure station of said camera;

means for exposing said material when it is so received in such exposure station;

means for selectively effecting a flow of such liquid from a source thereof to such material following exposure thereof; and

filter means for permitting passage of such liquid from such source to such material and for precluding passage of gaseous fluid whereby such liquid may be applied to such photographic material without including entrained gas in dispensed portions of such liquid.

2. The camera of claim 1 wherein said filter means comprises a porous filter medium which in cooperation with the surface tension of said liquid permits passage of such liquid and precludes passage of gaseous fluid within a given range of pressure differential applied to said medium, and said means for selectively effecting said flow includes means for establishing across said medium a pressure differential within said given range.

3. The camera of claim 1 wherein said filter means comprises a porous filter medium having a pore size in the range of 0.5 microns to 10 microns.

4. The camera of claim 1 wherein said filter means comprises a body of porous filter material having a mean pore size of approximately 1.2 microns.

5. The camera of claim 1 additionally including means for enclosing such photographic material following its exposure, said enclosing means being located in said camera at other than said exposure station, and means for transporting such photographic material from said exposure station to said enclosing means.

6. The camera of claim 1 additionally including a chamber in which such photographic material is positioned following its exposure, said chamber having at least one wall mounted for displacement between a first position where said chamber is opened to facilitate such positioning and a second position where said chamber is substantially closed around such photographic material, and said filter means is in communication with said chamber.

7. The camera of claim 6 wherein said chamber additionally includes a member which when said wall is in its second position cooperates therewith to define said chamber, and at least said wall or said member configured to engage a perimetric margin of the photosensitive surface of such photographic material when said wall and said member are in said cooperative relationship.

8. The camera of claim 1 additionally including a chamber in which such photographic material is positioned following its exposure, and means for permitting passage of gaseous fluids from said chamber, and precluding passage of liquid therefrom as said chamber is filled with such fluid.

9. The camera of claim 8 wherein said gas passing and liquid precluding means comprises a porous medium.

10. The camera of claim 1 wherein said means for selectively effecting the flow of said liquid includes a container for retaining such source of liquid and means for selectively varying the fluid pressure within said container.

11. The camera of claim 10 wherein said pressure varying means comprises a portion of said container configured for deformation responsive to application of an external force.

12. The apparatus of claim 10 wherein said deformable portion includes an elastic member which tends to return fluid pressure within said container to its original value upon removal of said force so as to reverse said flow of liquid.

13. The apparatus of claim 10 wherein said container comprises a deformable elastic bladder.

14. A camera for exposing photographic material and for applying processing liquid thereto, said camera comprising:

means for receiving such photographic material in an exposure station of said camera;

means for exposing such photographic material when it is so received in such exposure station;

means for selectively effecting reversible flow of such liquid between a source thereof andsuch photographic material following exposure thereof; and

filter means for permitting such reversible passage of such liquid between such source and such photographic material and for precluding passage of gaseous fluid therebetween whereby such liquid may be applied from such source to such photographic material and the unimbibed excess returned to such source without including entrained gas in such liquid.

15. Photographic apparatus for applying processing liquid from a source thereof to exposed photographic material so as to wet at least a portion of one of the surfaces thereof, said apparatus comprising:

means for receiving such photographic material;

means for selectively effecting a flow of such liquid from such source; and

means for directing such flow of liquid to such photographic material including filter means for permitting passage of such liquid within a given range of fluid pressure while precluding passage of gaseous fluid within said range of fluid pressure such that such liquid may be applied to such photographic material without including entrained gas in dispensed portions of such liquid.

16. The apparatus of claim 15 wherein said filter means comprises a porous filter medium which in cooperation with the surface tension of said liquid permits passage of such liquid and precludes passage of gaseous fluid within a given range of pressure differential applied to said medium, and said means for selectively effecting said flow including means for establishing across said medium a pressure differential within said given range.

17 The apparatus of claim wherein said means for selectively effecting flow of liquid includes means for selectively providing a predetermined pressure upon such source.

18. The apparatus of claim 15 additionally including a chamber in which such photographic material is positioned following its exposure, said chamber having at least one wall mounted for displacement between a first position where said chamber is opened to facilitate such positioning and a second position where said chamber is substantially closed around such photographic material, and said filter means is in communication with said chamber.

19. The apparatus of claim l5 additionally including a chamber in which said film material is positioned following its exposure, and said chamber including means for permitting passage exteriorly thereto of gaseous fluids and precluding passage of liquid.

20. The apparatus of claim 19 wherein said means permitting passage of gaseous fluids and precluding passage of liquid is a porous filter medium having sufficiently small pore size as to preclude passage of such liquid within said given range of fluid pressure.

21. A disposable dispenser of processing liquid adapted for mounting on photographic apparatus having means for supporting exposed sheet-like photographic material therein for application of such liquid thereto, said dispenser comprising:

a container for storing a source of such liquid; and

means including a porous filter medium in communication with said source for permitting passage of liquid from said container and precluding passage of gaseous fluid therefrom within a given range of source pressure.

22. The dispenser of claim 21 wherein said filter medium comprises at least a wall portion of said container, and said dispenser is configured for releasable mounting on such apparatus with said filter material in operable relationship to such photographic material.

23. The dispenser of claim 21 wherein at least a portion of said container is adapted for deformation responsive to application of an external force thereto so as to increase pressure within said container and establish on said filter material a predetermined pressure differential.

24. The dispenser of claim 21 wherein said container is a deformable elastic bladder.

25. A photographic process for treating photographic material with processing liquid from a source thereof, comprising the steps of:

conducting liquid from said source to said photographic material;

precluding conduction of gaseous fluids from said source t said photographic material;

returning excess liquid to aid source by conducting unimbibed portions of said liquid; and

precluding conduction of gaseous fluids from said photographic material to said source as said liquid is returned thereto.

26. The process of claim 25 additionally including the steps of enclosing at least a portion of the photosensitized surface of said photographic material in a chamber prior to said conducting step and removing gaseous fluid from said chamber prior to or during said conduction step.

27. The process of claim 25 additionally including the steps of supporting the surface of said photographic material opposite the photosensitive surface portion thereof, and forming a chamber around said photosensitive surface portion prior to said conduction step.

28. The process of claim 25 additionally including the step of depositing said photographic material within a chamber prior to said conducting step, and venting said chamber during said conducting step so as to permit escape of gaseous fluids from said chamber.

29. A photographic process comprising the steps of: I

positioning a sheet of photographic material for exposure of its photosensitive surface; exposing said photosensitive surface to photosensitize at least a portion thereof; conducting processing llqUlCl from a source thereof to said photosensitive surface and precluding conduction of gaseous fluids thereto; and returning excess liquid to said source and precluding conduction of gaseous fluids thereto. 

1. A camera for exposing photographic material and for applying processing liquid from a source thereof to such material, said camera comprising: means for receiving such material in an exposure station of said camera; means for exposing said material when it is so received in such exposure station; means for selectively effecting a flow of such liquid from a source thereof to such material following exposure thereof; and filter means for permitting passage of such liquid from such source to such material and for precluding passage of gaseous fluid whereby such liquid may be applied to such photographic material without including entrained gas in dispensed portions of such liquid.
 2. The camera of claim 1 wherein said filter means comprises a porous filter medium which in cooperation with the surface tension of said liquid permits passage of such liquid and precludes passage of gaseous fluid within a given range of pressure differential applied to said medium, and said means for selectively effecting said flow includes means for establishing across said medium a pressure differential within said given range.
 3. The camera of claim 1 wherein said filter means comprises a porous filter medium having a pore size in the range of 0.5 microns to 10 microns.
 4. The camera of claim 1 wherein said filter means comprises a body of porous filter material having a mean pore size of approximately 1.2 microns.
 5. The camera of claim 1 additionally including means for enclosing such photographic material following its exposure, said enclosing means being located in said camera at other than said exposure station, and means for transporting such photographic material from said exposure station to said enclosing means.
 6. The camera of claim 1 additionally including a chamber in which such photographic material is positioned following its exposure, said chamber having at least one wall mounted for displacement between a first position where said chamber is opened to facilitate such positioning and a second position where said chamber is substantially closed around such photographic material, and said filter means is in communication with said chamber.
 7. The camera of claim 6 wherein said chamber additionally includes a member which when said wall is in its second position cooperates therewith to define said chamber, and at least said wall or said member configured to engage a perimetric margin of the photosensitive surface of such photographic material when said wall and said member are in said cooperative relationship.
 8. The camera of claim 1 additionally including a chamber in which such photographic material is positioned following its exposure, and means for permitting passage of gaseous fluids from said chamber, and precluding passage of liquid therefrom as said chamber is filled with such fluid.
 9. The camera of claim 8 wherein said gas passing and liquid precluding means comprises a porous medium.
 10. The camera of claim 1 wherein said means for selectively effecting the flow of said liquid includes a container for retaining such source of liquid and means for selectively varying the fluid pressure within said container.
 11. The camera of claim 10 wherein said pressure varying mEans comprises a portion of said container configured for deformation responsive to application of an external force.
 12. The apparatus of claim 10 wherein said deformable portion includes an elastic member which tends to return fluid pressure within said container to its original value upon removal of said force so as to reverse said flow of liquid.
 13. The apparatus of claim 10 wherein said container comprises a deformable elastic bladder.
 14. A camera for exposing photographic material and for applying processing liquid thereto, said camera comprising: means for receiving such photographic material in an exposure station of said camera; means for exposing such photographic material when it is so received in such exposure station; means for selectively effecting reversible flow of such liquid between a source thereof and such photographic material following exposure thereof; and filter means for permitting such reversible passage of such liquid between such source and such photographic material and for precluding passage of gaseous fluid therebetween whereby such liquid may be applied from such source to such photographic material and the unimbibed excess returned to such source without including entrained gas in such liquid.
 15. Photographic apparatus for applying processing liquid from a source thereof to exposed photographic material so as to wet at least a portion of one of the surfaces thereof, said apparatus comprising: means for receiving such photographic material; means for selectively effecting a flow of such liquid from such source; and means for directing such flow of liquid to such photographic material including filter means for permitting passage of such liquid within a given range of fluid pressure while precluding passage of gaseous fluid within said range of fluid pressure such that such liquid may be applied to such photographic material without including entrained gas in dispensed portions of such liquid.
 16. The apparatus of claim 15 wherein said filter means comprises a porous filter medium which in cooperation with the surface tension of said liquid permits passage of such liquid and precludes passage of gaseous fluid within a given range of pressure differential applied to said medium, and said means for selectively effecting said flow including means for establishing across said medium a pressure differential within said given range.
 17. The apparatus of claim 15 wherein said means for selectively effecting flow of liquid includes means for selectively providing a predetermined pressure upon such source.
 18. The apparatus of claim 15 additionally including a chamber in which such photographic material is positioned following its exposure, said chamber having at least one wall mounted for displacement between a first position where said chamber is opened to facilitate such positioning and a second position where said chamber is substantially closed around such photographic material, and said filter means is in communication with said chamber.
 19. The apparatus of claim 15 additionally including a chamber in which said film material is positioned following its exposure, and said chamber including means for permitting passage exteriorly thereto of gaseous fluids and precluding passage of liquid.
 20. The apparatus of claim 19 wherein said means permitting passage of gaseous fluids and precluding passage of liquid is a porous filter medium having sufficiently small pore size as to preclude passage of such liquid within said given range of fluid pressure.
 21. A disposable dispenser of processing liquid adapted for mounting on photographic apparatus having means for supporting exposed sheet-like photographic material therein for application of such liquid thereto, said dispenser comprising: a container for storing a source of such liquid; and means including a porous filter medium in communication with said source for permitting passage of liquid from said container and precluding Passage of gaseous fluid therefrom within a given range of source pressure.
 22. The dispenser of claim 21 wherein said filter medium comprises at least a wall portion of said container, and said dispenser is configured for releasable mounting on such apparatus with said filter material in operable relationship to such photographic material.
 23. The dispenser of claim 21 wherein at least a portion of said container is adapted for deformation responsive to application of an external force thereto so as to increase pressure within said container and establish on said filter material a predetermined pressure differential.
 24. The dispenser of claim 21 wherein said container is a deformable elastic bladder.
 25. A photographic process for treating photographic material with processing liquid from a source thereof, comprising the steps of: conducting liquid from said source to said photographic material; precluding conduction of gaseous fluids from said source to said photographic material; returning excess liquid to aid source by conducting unimbibed portions of said liquid; and precluding conduction of gaseous fluids from said photographic material to said source as said liquid is returned thereto.
 26. The process of claim 25 additionally including the steps of enclosing at least a portion of the photosensitized surface of said photographic material in a chamber prior to said conducting step and removing gaseous fluid from said chamber prior to or during said conduction step.
 27. The process of claim 25 additionally including the steps of supporting the surface of said photographic material opposite the photosensitive surface portion thereof, and forming a chamber around said photosensitive surface portion prior to said conduction step.
 28. The process of claim 25 additionally including the step of depositing said photographic material within a chamber prior to said conducting step, and venting said chamber during said conducting step so as to permit escape of gaseous fluids from said chamber.
 29. A photographic process comprising the steps of: positioning a sheet of photographic material for exposure of its photosensitive surface; exposing said photosensitive surface to photosensitize at least a portion thereof; conducting processing liquid from a source thereof to said photosensitive surface and precluding conduction of gaseous fluids thereto; and returning excess liquid to said source and precluding conduction of gaseous fluids thereto. 